I was having problems with some of the lighting on my 93 Lx Wagon when I first brought it home. None of the brake lights, turn signals (except 1 of the fronts), the reverse lights, nor the dome lights worked. The headlights were rather dim as well. I couldn't find any problems within the wiring, but I noticed that the metal inside the bulb sockets themselves had began to get oxidized , and green in one of the lights that had a leak. I sanded what I could and put vinegar on the rest (like resurfacing a dirty penny), and everything came back to life. Also made sure the bases of the light bulbs were free from oxidation or rust. I cleaned the bases all the vinegar and everything came back to life. With the exception of the main dome light bulb, I haven't had to buy or change any other lighting. It made a big difference on my headlights as well as all around the car.
The thing on ABS was an interesting read. I used to work in the plastic department of a sign shop. Sometimes when really expensive faces and parts got yellowed you could clean them with steel wool to take the top layer off without grooving and gourging the plastic, then use an industrial plastic polish and light buffer to make them clear and shiny again. There are so many different products out there. I would certainly make sure it is rated for abs and you follow the instructions closely. If you put the wrong stuff on the wrong plastic you can pretty much ruin them. Some are simply cleaners, while others essentially dissolve and resurface the plastic. Maybe try on an old set or some from the junkyard if you get some of it. Also I had alright luck with generic auto part store plastic restorer on a really bad set of headlights I had on my previous car ('00 Impala). I think it was the Pep Boys brand, or whatever the cheapest was. They weren't 100% but a considerable improvement.